Solvent material for absorption refrigerating machines



soLvEN'r' MATERI'AL Fort ABsonr'rroN anmronna'rnvo-monmns Glenn zellhoeferpliloomington, Ill.

No Drawing. Application April 20, 193 4, Serial No. 721,549

IOlaim. (01.25pm A This present invention relates generally to sol- Briefly described, the apparatus specifically event matetialsforg absorption: refrigerating. maereferred,toacomprises a still in which a mixture nines, and-particularly to thetype of solvent ma of solvent and refrigerant is. heated tovaporize terial for, the so-called two-fluid machines, the refrigerant from the solution, a condenser 5 wherein there is a solvent material adapted to rewherein the vapor is condensed to a liquid state, main liquid throughout the operation of the rean evaporator wherein the liquid is vaporized i'rigerator, and'a refrigerant material adapted to at reduced pressure, such evaporator being the have a liquid and a vapor phase in the cycles of fi i cooling means, Su as 00118. in the -D- operation, and adapted to be dissolved in the solparatus, and an absorber in which vapors conm vent. taining added heat units are again dissolved in 10 Numerousrefrigerants and solv t a d nuthe solvent. Suitable heat exchanging and cirmerous combinations are known, A numb f culation means are included, and automatic conpublished articles are known which deal with a trOlS ay be P v ded. listing of refrigerants, and a listing of solvents. The Particular Characteristics of Su h Ina- 1:, These publications appear to be ba d upon chines are that the still operates at temperatures knowledge of certain successful combinations of a l v n rm temper against which solvent and a'r'efrigerant. On the basis of sucthe refrigeration act such for example at cess in these combinations, certain conclusions -;'a d t at t e cooling unit Operates at t p are drawn, and it is predicted that other combietures much ow r than normal, uc as f nations of the listed materials may be made. to Various Parts Of the apparatus d fi 20 However, to one skilled-in the art and having in the prevailing pressures as well as temperaknowledge or other properties of the listed mar s d b th pr ssu and t p atu d t rterials not considered in these publications, and a m ne t P y l tate of the fr e r fri r knowledge of practical considerations, it is obvi- Whether geseeus q d te m e t e- :5 one that th predictions cannot b li upon, solubility relations between the refrigerant and and that many. combinations are not operable, the solvent It therefore, y important that or if operable, are not practical, and could not be Solvent and the refrigerant b physi al y successfun 'u di r ia refrigerating 1 adapted for use as individual materials in cert tain places and for certain functions, and that I The present invention relates to solvents for the t be mutually p e for certain u et e '30 refrigerant methyl chloride. Although there are e y a in i ti Other qu ities many solvents apparently-available from t 11 not essential to refrigeration, but pertinent to ings refererred to, there is no differentiation of preetieel usa e, control or limit the choice of solthem for particular refrigerants. When 1 advent or refrigerant, such as odor, viscosity, heat here to one material as [a refrigerant, namely, capacity, boiling P freezing P V y, 3'5 methyl m I am vable t carry out certainchemical stability, reactivity, corrosive action, in-

tests which will determine the suitability of a flammability, toxicity, 9

given substance as a solvent for it. By numerous y on of the limitations which I have diste t a experiments I have been able to set covered and have herein-set forth, I have been to, limitationsiwhich determine whether a solvent is eble divide compounds ntaining the struc- 4 a suitable one for successful practical use with tllre C+OC into one group which is suitth l h o i i 1 able and into another group which is unsuitable. H As a. resultof the limitations and the tests, I have o found that although there are h Q. have discovered that certain compounds containcompounds f d in th P art listings above ing the ether group h e alluded to, these fall into the unsuccessful group 7 '1. m t combinations of properties tending t when tested by the limitations which defines the L we e s es, PATENT OFFICE make t anew class in which one is quite successful group of ethers constituting the prestainto find apractical,refrigeration solvent for ent lhventien- :methyl chloride. However, "II have discovered Y In defining the p ds I t d to nclude to that every. such compound is not suitable, for compound in which the ether p f Structure 1 one reason or another. is found, namely, l

a An example of an apparatus in which the new 50 materials have been successfully employed is de-- 1 v iggeamm retentiv 1,895,698, January 31,, a I

that is, an oxygen atom connected to two carbon .1 Of this invention atoms. It-permits of the two carbon atoms being otherwise unlinked, being linked directly together, orbeing members of a ring structure through linkages beyondthe immediate carbon Inipractical usage the solvent may exist substantially alone, and also in varying proportion in admixture withimethyl chloride. It is subjected to varyingtemper'atures and pressures within certain normal working ranges. Since the solvent 15 is used for dissolving, containing, and discharging methyl "chloride with respect to the vapor phase of the latter, the

, 'tantf Stability ofythesolvent commercial-'liife-of the refrigerator unit, and this n-butyrete of the mono-n-butyl ether of ethylene glycol 'metals, with the BB dichloroethylether temperature and pressure are conjointlymaterial to successful operation. Since viscosity is pertinent. Since the solventmust contact metal structures, chemical activity is imporis necessary for.

must" be considered both in regard to its inherent stability-and itsstability in contact with i methyl chloride, and withtraces of water or water vapor which might be present.

3 at 760 mm.

" 3. Freezing point.-Not over F. (-12 C.)., 4. Stability and activity.-Must be chemically- .stable and inert at or below 270 F. (132 C.) in

Thedifferential solvent power of the ether for methyl chloride is material for determining an overall proportion in the unit between solvent lowing specifications:

1. Viscosity.--Not over 10.0 centipoises at C. (77 F.).

2. Boiling. point.Not under 270 F. (132 0.)

the presence of methyl chloride, iron, steel, cop- 4 per, bronze, brass, and moisture. there is flow of liquid inpipe-like apparatus, the, 20

5. Solvent power for methyl chloride-There must be a minimum of 0.14 gm. per cc. difference insolubilities at lbs. pressure at 90 F., and at 90 lbs. pressure at 230 F.

*Ihave applied these tests to the following solvents, and have also used the materials in combination with'methyl chloride in a two-fluid unit of the kind above described, finding all of them satisfactory for commercial usage.

Acetate of niono-butyl ether of ethylene glycol I Acetate oi diethylene glycol mono-butyl ether memom-o-cmomoz Dichloroisopropylether omen-0mm .omtm-cmci Dlchloropropyl ether oion,on,om o-omcn,omol' cmwmn-p-cnmmon omen)r-o-omomoomomon cmwmnocmcmo-ooom onaonmoomomoomonloooom omwnmocn cmocownelcm Methoxyacetate of the mono i-butyl ether of ethylene glycol, CH;(CH,);OCH,OH=0COCHzOCH;

Diethylene glycol'mono-butyl ether chloride Dimethyl other of triethylene glycol -Q Acetate of ethylene glycol mono-tetrehydroiurluryl ether ..-CH3OHI $11: (5H-OHr0-OH1CH2-OCOCH:

a 0 'letrahydreiuriuryl n-butyl ether of ethylene glycol Shir-OH,

\ 3111- HOH:O--OH;OHg-O-0H;CH,OH;OH;

O Ethyl furoate ROUGH HG OC -O 01H:

Tetrehydrofurluryl ecetete.. CH; 0H|

C CHCH,OCO0H;

jurturyl HO *[OH no x 0-0 15:

lm'turylaeetate HG |"CH B-bromoethyl phonyl other p-chloro plienotolo i course one ether may be considered as better than others, but all those specified herein are commercially adaptable ior producing reirigeration. Accordingly, I do not choose to differentiate between those herein listed.

Examination of the list will show that there is a wide variety of derivatives which suggest to those skilled in the art, certain substitutions or changes in the chains or groups which are attached to the essential ether structure It will be observed, for example that furfural ita self has an ether group in its structure; that some compounds, such as diethylene glycol mono-butyl ether have two of the ether linkages; that othersi have three; and that still others have four. It is, therefore, to, be understood that the essential Q iact that there is an ether structure present in the formula.

An ether structure is essentially an organic Z oxide, and like metal oxides. these are quite stable ether grouping Phenoxypropyl bromi '7 I c-o-omomcmm 1 .J I v r p-bromophenetol lg:-

\ HC on no on v ()CzHu I Ethylene glycol mono-ethyl enmtam".-. omomocmomococn,

compounds. I have found that the stability of the EC-O-C is retained when the bonds to. the ether carbons are attached to atoms from the list: carbon, oxygen and hydrogen. Howevenwhen a halogen atom is'attached to one of the ether carbons the halogen derivative is active. Therefore, an ether such as dichloromethyl (CHzCLQCHzCl) is eliminated on the basis of structure. It is also eliminated because its physical characteristics lie outside of the field above defined.

It is to be noted that the compounds containing the said ether structure are not of any one specific organic class, and include groups selected from many types of organic compounds.

These include cyclic compounds such as furiural; cyclic compounds containing an ester group, as furfuryl acetate, ethyl furoate, tetrahydrofurfuryl acetate; halogen derivatives of a simple compound, as dichloroisopropyl ether, vdichioro-- propyl ether, dichloroethyl ether; an aliphaticaromatic ether, with a halogen in the aliphatic chain, .as bromo-ethyl phenyl ether, phenoxy propyl bromide; aliphatic-aromatic compounds with halogen on the aromatic nucleus, as bromophenetole, "chlorophenetole, fluoroanisol; compounds containing an alcohol group, as in ethylene glycol mono-butyl ether, and diethylene glycol mono-butyl ether. Examination of the list above given shows how the groupings attached to the ethercarbons maybe altered without destroying include all of them,

I tether grouping several new solvents specifically within. the field above set forth.

It is to be noted that in claiming compounds having the ether structure, I do not intend; to .but only, those having the limitations herein described. I claim as my discovery thatthere is something inherent-in the which makes this class of compounds successful as a solvent for methyl chloride, and that this is particularly true when the ether carbons are attached only to atoms from the list: carbon, hydrogen and oxygen.

The art recognizes that the mixture of solvent and refrigerant which is useful in a two-fluid absorption machine, is also useful in a three-fluid absorption machine in which an inert gas is a third ingredient which does not enter into a three-phase homogeneous mixture in any condition of operation of the machine. The function of the gas is pertinent to mechanical changes in the physical mechanism which operates on the refrigerant and solvent or the combination of refrigerant and solvent. Hence it is intended that he claims are directed to a refrigerant mixture broadly for absorption types of apparatus."

The applicant has disclosed the suitablity of for methyl chloride. This is a common example of a highly, volatile refrigerant for which it is known that others may be substituted. It is therefore intended" in" the accompanying claims to set forth the newsolvents as additions to theknown lists of solvents,- the additions being herein described members which are peculiarly adapted for the usage because of the presence of one or more characteristic ether groupings. i

The presentapplication is a continuation in part of my prior application, and is intended to be generic in character to my application Serial No; 687,045, filed August 28,1933, now Patent No. 1,991,240, wherein I disclosed BB dichloroethyl I ether as a solvent for methyl chloride.

-Applicant's copending application Serial No.

17,064, filed April 18, 1935, as a continuation in part of this case, is generic to subject matter herein disclosed.

v The applicant's later copending application Serial No. 17,064, filed Ap.il 18, 1935, is generic to combinations here claimed with methyl chloride; and the applicant's copending application Serial No. 756,982, filed December 11, 1934, as a continuation in part of this application, is specific to the solvent dimethyl ether of triethylene glycol.

The applicant's copending application Serial No. 19,597, filed May 3, 1935, as a continuation in part of this application, is specific to the solvent ethylene glycol monoethyl ether acetate, and is generic to the combination of it with methyl chloride.

The applicants later application Serial No. 756,981, filed December 11, 1934, as a continuation in part of this application as to the solvent tetrahydrofurfuryl acetate, is specific with respect thereto; and Serial No. 17,065, filed April 18,

1934, as a continuation in part of this case and of Serial No. 756,981, is generic to such solvent.-

The applicant's later application Serial No. 19,598, filed May 3, 1935, as acontinuation in part of this case, is generic to the combination involving tetrahydrofurfuryl ether of ethylene glycol acetate.

What I claim is:

A refrigeration mixture comprising as essential ingredients methyl chloride as a refrigerant and solvent selected from the group of alkyl ethers of the ethylene glycols consisting of ethylene glycol mono-butyl ether, diethylene glycol monobutyl ether, acetate of mono-butyl ether of ethylene glycol, acetate. of diethylene glycol monobutyl ether, n-butyrate of the mono-n-butyl ether 

